


a friend of lightning

by Kinyve



Category: Pocket Monsters | Pokemon - All Media Types, 鬼滅の刃 | Demon Slayer: Kimetsu no Yaiba (Anime), 鬼滅の刃 | Kimetsu no Yaiba (Manga)
Genre: Established Relationship, Fluff, M/M, a bit zenitsu and mareep centric, tanjirou is a supportive boyfriend, team rocket being assholes
Language: English
Status: Completed
Published: 2019-10-14
Updated: 2019-10-14
Packaged: 2020-12-16 00:34:58
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,262
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21027344
Author URL: https://archiveofourown.org/users/Kinyve/pseuds/Kinyve
Summary: Zenitsu's not the best with pokemon, so he chooses not to have one.(pokemon au where zenitsu adopts an overpowered mareep but he doesn’t know it yet)





	a friend of lightning

**Author's Note:**

> i should've reviewed for tomorrow but i need to keep up this writing streak to prepare for tanzen week

“You’re going out _again?_” Zenitsu asks Tanjirou, who's brushing Arcanine's fur to perfection. 

It's only been half a week in and Tanjirou's already off travelling to Kanto.  He's a bit salty to see his boyfriend leaving on and off so sporadically, but he understands. Trainers don't really like to be bound to one place, they like exploring and catching different Pokemon species.

Zenitsu knew what he was getting into, dating this lovable _nerd_.

Still, it wouldn't _kill_ for Tanjirou to stay a little more. “Don’t you get tired, Tanjirou?”

“Of course not! There’s a whole region to explore!!” Tanjirou grins at him, patting Arcanine's mane in pride.

To Zenitsu the thought of exploring a whole region only tires him out, but he's not about to dampen Tanjirou's spirits, so he smiles back.

Tanjirou fishes a pokeball out of his belt and tosses it up the air with a whistle. Arcanine jumps up to catch, pressing the button with his teeth as he bites, and it inevitably sucks him in.

Zenitsu rolls his eyes when Tanjirou catches the ball back in his hands. Show off.

Tanjirou notices, but decides to ignore it. “You should get a Pokemon too Zenitsu.” He says instead. "You can join me." _So I don't have to always leave you here_, that part is left unsaid, but Zenitsu knows anyway.

He was wondering when the old '_you should get a pokemon_' topic would be brought up. Well, he guesses it's here now.

The blonde sighs, scratching his head.

Zenitsu, despite his countless friends who have them, does not have a pokemon.

His grandfather has tried getting him to warm up to the idea, but he always declined. Ever since that one lightning pokemon struck him intentionally--_so strong that it fried his hair blonde_\--he became too afraid of what the little critters are capable of.

So, much to the chagrin of his grandpa and his step-brother, Zenitsu cannot step out of Ecruteak City.

Granted, he doesn't want to anyway. The city has everything he could afford to live on--food, shelter and all kinds of stuff.

Zenitsu shrugs,“I can barely take care of myself. I think my Pokemon's just going to hate me.”

Tanjirou pouts, irked at his answer, but moves to pull the blonde into a hug. “Well, just take care okay?” He squeezes tight, humming as he does.

Zenitsu grins into his shoulder, hugging back with just as much force. Despite being the more sentimental of the two, Tanjirou's the one who always says goodbye, how ironic.

“Sure, sure.” He dismisses, trying not to let the sudden feeling of loneliness wash over him. He should be used to it by now. “Bring me a souvenir from Kanto.”

Tanjirou gives him a gentle peck on the cheeks, reassuring him.

* * *

Zenitsu finds nightly walks to be really calming.

It's a time where the bustling city is reduced to the quiet chirps of a Pineco in the trees, and a time where people dwindle in the streets.

He appreciates it, mostly because he doesn't do well with noise in general. He has the tendency to be quite jumpy and he'd panic at unfamiliar sounds, but at night he can feel a little more at ease, because all you hear is the wind and idle chatter from the Pokemon in the bushes.

Even though his grandpa forbids it, he still manages to sneak out to Route 42 almost every night, where he likes to just camp out and watch the moon. There's a large open space just before the cave, and it's the perfect place to just lay a blanket out and have a goodnight's sleep.

Today too, he ventures out to the open space. The blanket's still churning in the dryer back at home, so he has to settle for direct contact on the soil for today.

It's going well so far, he's just looking at the sky as he normally does--

\--until he hears wailing from the cave.

Zenitsu can be brave--_somewhat_\--but now? He's absolutely terrified.

So he does the logical thing and walk closer.

It didn't sound human, that's for sure, and his mind immediately wanders to Haunters and Ghastlys.

Do they make sounds? He's not really sure.

But either way, the crying didn't sound like one of those horror movies, so he steels his resolve, just in case someone was actually hurt and he ends up risking their life by running away.

He inches slowly to the cave entrance, swallowing as he shakily takes a peek inside.

It's _dark_.

Zenitsu resists the urge to just up and leave. There's gotta be something in here.

The crying resounds again, and this time it's a little louder. 

Whatever it is, it's inside the cave somewhere.

Zenitsu inhales deeply.

He's not supposed to be doing this, it's stupid trying to take even one step inside caves or grass, for the sole reason that a pokemon could possibly maim him. He doesn't have protection like the trainers do.

But something about right now, and hearing that painful crying, makes him want to charge ahead.

So he grits his teeth, says a vague prayer, and he enters.

He meekly takes steps to the sound, opening his Pokegear to get some light.

The howling grows louder as he walks further, and eventually, he sees sparks of lightning somewhere in front of him.

Oh no.

He slowly and shakily moves his light up, and finds himself face to face with a fluffy ball of yellow fur, shivering. It's physically hurt from all of the scratch marks and cake blood on its face.

Zenitsu, being scared the most of electric types, almost dips then and there. 

But seeing the creature look at him in fear stops him.  It's not hostile. Pokemon are more scared of you, he remembers his gramps would say.

Still, he doesn't know how to help. His grandpa would always say never to touch a wild pokemon, and the little guy is too shaken up to talk to properly-- 

He doesn't get to think any further when he hears a hiss of a snake behind him.

Zenitsu immediately drops down to hug the hurt pokemon, and for a second, he accepts his fate of being electrocuted for the second time. But worriedly enough, the fluff ball doesn't struggle only seemingly accepting its fate.

He turns back to see an Ekans sizing him up, looking angry that he's there protecting his meal.

Oh _fuck_, is this how he dies? By getting poisoned to death?

Zenitsu hears a mewl in his arms and he looks down to see the pokemon staring up at him. It almost looks like it's telling him to just leave and don't bother,  it was about to die anyway.

He only hugs it tighter.

The Ekans' hissing grows aggressive, approaching slowly as it bears its fangs.

The Pokemon in his arms struggles and keens, but he shushes it with kind hums. 

Human or not, Pokemons were still emphatic creatures, and as much as he didn't like them, obviously a lot of people do. He can't just let this little guy die so painfully.

He'll at least provide a buffer for it to escape.

Ekans, finally having enough, lashes out and--

"Flame thrower!"

\--_is immediately engulfed in flames_.

Zenitsu yelps, ducking from the stream of fire coming from behind, overhead. The cave lights up with the attack and Zenitsu faintly wonders _who the fuck thought it was a great idea to use fire inside?! Does the cave have ventilation?! Is he going to die from the fumes?!_

"Zenitsu!!"

_Oh_. Zenitsu realizes, Of _course_ it's Tanjirou.

He doesn't get to turn back because Tanjirou's already tackling him to the ground.

"What were you doing?!" He scolds, smushing his cheeks together as he holds the blonde's face. "You know it's dangerous for you to wander around in bushes, even more so in caves!!"

And Zenitsu, overwhelmed from the fact that _yes he did do something as stupid as that_ and how he almost risked his life dying of poison, cries.

He minds the Pokemon in his arms, trying not to squish it as he buries his tears into Tanjirou's shoulder.

"_I'm sorry_," He hiccups, feeling arms wrap around him in comfort. “_Tanjirou. He was hurt so—_“

Tanjirou doesn't let him say anything more, only giving him a soft kiss to the corner of his lips and helps him stand up.

* * *

Unfortunately the blonde, after dropping the Pokemon in the center last night, the next morning Zenitsu wakes up to a scolding by gramps.

“_Zenitsu._”

The blonde flinches to attention. The pokemon in his arms blinks.

“Hi, gramps.”

“Tanjirou told me what happened.”

He gives Tanjirou a look, and his boyfriend looks guiltily to the side. As always, he can't lie.

“_Uh_—“

His grandpa slams his hands on the table.

“You _refuse_ to have Pokemon, and then I just hear about you diving straight into a _cave?!_”

Now that he hears it from an elderly's voice, he realizes just how stupid his actions were last night. If it weren't for Tanjirou conveniently showing up, he'd be dead by now.

Still, he has to stand his ground. 

By stuttering wildly.

“Look, gramps, I—there was a—what do you call them—“

“A Mareep.”

Zenitsu snaps his fingers, face red in embarrassment. “Y-Yes. That.” He didn't have all the Pokemon in their region memorized, unlike gramps. It doesn't help with his case, probably. 

“It looked hurt and I just—“

They stare at each other, one with a glare and one with a wilting gaze. Zenitsu knows saving a Pokemon is a weak counter-argument to you almost died in that cave.

“Alright." His grandpa finally relents with his glare, gaze softening as he leans back in his chair. "I can’t scold you too much for something that’s already happened.” 

He motions for Zenitsu to come closer and the blonde, expecting one of his usual smacks to the head, comes forward meekly and bows his head.

Instead, all he gets is a soft pat on the head and a relieved smile.

“I’m just glad you’re safe.”

Zenitsu almost cries again then and there. Sometimes he forgets he's not actually related to him, and that he's just an old man who picked up a kid who got electrocuted.

The Mareep in his arms chirps, and their attention is immediately on the small Pokemon.

“Are you planning on keeping it?”

“_Huh?_”

“The Mareep. You _did_ save it.”

And Zenitsu doesn't know how to reply because he's not really sure himself.

* * *

Zenitsu awkwardly hangs a berry over Mareep's head.

“Hi, there, um.” He doesn't really know how to talk to Pokemon, but he's been aware that this Mareep was young and that he should be careful with his words.  He keeps his voice as sweet as possible. “How are you feeling?”

Mareep stares unblinkingly.

“_Tanjirou it’s not responding—_“

“_He’s_ listening.” Tanjirou corrects gently, nudging him forwards ever so slightly. “Come on, don’t be scared of him.”

_Easy for you to say_, he hisses in his mind, _pokemon love you even if they meet you for just a second._

Maybe they can sense that Tanjirou's a good person? This Mareep probably thinks he's a creep then.

Tanjirou hands him a pokeball, curling Zenitsu's hands around it using his own. The warmth reassures him a bit and he finds the courage to talk to Mareep some more.

"Hey, buddy." He places the berry in front of Mareep, and waves the pokeball gently at his face. "Do you mind if I, uh, catch you with this ball?"

Still no reply.

"I know you might not like being isolated in this thing, but it's safer than the outside, you know?"

Mareep tail twitches a little, still not a peep, but he thinks he's making progress.

He doesn't really know what else he could say, though. "I'll just," He places the pokeball on the ground to, just a few inches from the berry. "Let you do it."

At first he thinks Mareep's not going to do anything at all, and that he might just really have to return him to the wild to live its life, but the pokemon actually does move, much to his relief.

It steps forwards cautiously, picking up the berry with its mouth. Zenitsu resists the urge to scream in success, afraid of startling him. Mareep regards the pokeball with interest, and he looks up at Zenitsu.

Zenitsu tries to give him what he hopes is a kind smile, emulating his inner Tanjirou.

Then Mareep takes a few more steps and nudges the button on the ball, it rolls away at first, but Zenitsu steadies it for him.

Mareep is sucked in with a small mewl.

Zenutsu stops holding his breath, and Tanjirou beside him finally reacts.

"_Zenitsu!!_" He yells, jumping to hug him. "I'm so proud of you!!"

Zenitsu can't stop the grin on his face as he returns Tanjirou's hug.

* * *

He should've taken a detour.

Zenitsu's stomach feels like it's on fire as he collapses on the grass. He hears Mareep's cries from somewhere in front of him.

The grunt who just gave him a punch to the gut turns around, dismayed. "What?!" Zenitsu angles his head, blearily able to make out his expression. "Don't tell me this is the _only_ Pokemon you_ have?!_"

Another one of the grunts clicks his tongue, throwing Mareep down to the ground with force. Mareep yelps in pain. "Pathetic."

"_Don't--!!_" He regains the energy to stand and charges, but he ends up getting another hit to his sides.

"Shut up for a second, will you?!" A girl grunt shouts, annoyed. "Man, I'm telling you. Do we even have to take his pokemon? He doesn't even know how to battle with them."

The same grunt who threw the punches at him laughs, "Yeah, she's got a point." He kicks the Mareep slightly as it tries to pitifully stand. "And this little guy only knows one move."

"Shut up." Another grunt scolds, "We were asked to get _any_ trainer with pokemon. Even the shitty ones."

_He's going to kill them_, he thinks as he watches Mareep fretfully skitter towards him. Wasn't team rocket already abandoned back in Kanto? Why here? Why now?

He should've listened to Tanjirou about the rumors he was hearing.

He struggles to get up and move, _he needs to protect Mareep_. His pokemon doesn't deserve this, _any_ pokemon doesn't deserve to be--

"Still awake?" He hears a cackle from above. "You've got a hard head, let me fix that."

He's hit bluntly on the head with much force, and he ends up on the ground for good. He hears ringing in his ears and his vision turns blurry as he groans, trying to make sense of his surroundings.

His Mareep yowls for him, distressed as it keeps trying to nudge him awake.

Zenitsu reaches out for him, hands gingerly grazing the soft fur before his hands drops down, feeling too woozy to move anymore limbs.

_ I'm sorry Mareep. I couldn't save you twice. _

What a worthless trainer he was, letting his Pokemon get taken away from him.

Then Zenitsu sees black.

* * *

"Geez, I think you beat him up too much." The girl grunt huffs, watching the blonde lose consciousness.

The grunt who delivered the blow frowns. "Hey, it was just three hits man. And it makes this easier." He stretches his shoulders and arms, "Now let's--" He looks around for the Mareep, only to find it just near his feet.

Mareep's still nudging his trainer's arm, begging him to wake up with its chirps and cries, sounding desperate.

One of the grunts rolls his eyes at the sight, "Aw, that's cute but you're gonna have to come with us, okay?"

Before they can approach it again, however, electricity suddenly mars the pokemon's fur, and sparks fly around the air. It's tail glows.

One of the grunt's hairs stands up and he swears, "Guys I don't think--"

Suddenly the air is vibrating with energy, the sparks grow thicker and--

\--Mareep is staring soullessly at them.

A large bolt of thunder rains down from the heavens, a pillar as thick as a tower just about frying every grunt in sight with a large boom of sound.

* * *

Tanjirou turns around, eyes trained on the forest behind him.

Thunder?

* * *

Zenitsu wakes up with a start, and feels his whole body aching.

But that's the least of his problems.

"_Mareep!!_" He shouts, remembering the events that occurred before he blacked out. _Did he get taken away?!_

Something stirs beside him, and the feeling of a soft blanket over his lap makes him calm down from his sudden shot of adrenaline.

So he's back at home, in his room--

"Ow." Someone beside him mutters, and he's surprised to see Tanjirou there, cradling his ear.

_ \--with Tanjirou? _

"What are you doing here?" Was all that just a fever dream? Though, judging from the pain he feels on his head, sides and gut, it was a _very_ real encounter.

But he pays the pain no mind, trying to slip off the bed as he fret for Mareep. "Where's--"

"Mareep? He's right there." Tanjirou gently pulls him back, pushing him down to the mattress with enough force. He looks a little bit annoyed, probably at being woken up. "Now _calm down_, you're still injured."

Zenitsu winces when he releases the tension on his abdomen from sitting, _yeah_ he can agree with Tanjirou, he's injured alright.

"Good thing I followed the sound of thunder." Tanjirou sighs and pulls the blanket up on both of them, letting Zenitsu lean most of his weight on him. "I panicked seeing you passed out like that, you know?"

Zenitsu remembers the blow to his head and hopes it didn't give him anything too serious. "Sorry." He murmurs into Tanjirou's shoulder. He's sorry for the both of them, for getting himself hurt and making Tanjirou worried.

"I didn't expect team rocket to just show up out of nowhere."

Tanjirou hums, "Good thing you had Mareep."

The mention of him revives Zenitsu's worries, "Did he get hurt?" He's not trying to sit up anymore, but Tanjirou keeps him in place just in case. "I tried to stop them from taking him but--"

A kiss on the forehead stops his running mouth, "He was_ fine_. He came out mostly unscathed." Tanjirou runs a hand through his hair and he immediately melts. The worry is still there, but Tanjirou's a damn good distraction. "But I gave him a few spritzes of potion to make sure."

"Thank you." Is what Zenitsu can only sigh out, the feeling of the touches and the bed succeeding on calming his nerves. "Mareep is really quiet, so I don't know what he's thinking half of the time."

Tanjirou laughs, and Zenitsu cherishes the sound. "You're doing great. He loves you a lot already."

"Really?" He doubts that, sometimes he even forgets to feed the poor Pokemon on time. He's pretty sure Mareep's at least a _little_ annoyed about that.  "He doesn't really talk to me." 

Zenitsu blinks, realizing he sounds stupid.

"I mean, _obviously_ he can't _talk_ to me but--"

This time the kiss aims for his lips, and it lingers for a while longer than earlier. 

"Trust me." Tanjirou murmurs when he pulls away, "For now, worry about yourself more, okay? You got hurt too."

Zenitsu doesn't reply anymore, too comfortable on the bed and already knowing Tanjirou's stand will not budge.

He gives the pokeball on the nightstand a smile, and hopes Mareep is having a goodnight's sleep too.

**Author's Note:**

> extra notes:  
inosuke lives in kanto, originally in pewter city, but now he kinda wanders. he still visits his ol grandma tho  
tanjirou lives in violet city, nezuko stays there with their family, and they own a pokemon daycare  
hashiras are either elite four members or old champions


End file.
